Since the early days of computers, efforts have been made to improve intuitive and realistic interaction between humans and computers. From mouse to touchscreen interface technologies, making a user's experience with their computer more lifelike and intuitive has been a key for increasing productivity and advancing how people can use and interact with their digital worlds. Virtual Reality (VR) is an artificial digital world that consists of images and sounds created by a computer, viewed and heard by a user, and at times affected by the actions of the user who is experiencing it. Augmented Reality (AR) is an augmented version of reality created by the use of technology to overlay digital information of an image on or in something being viewed through a device (such as a smartphone camera). Although all forms of human-computer interaction could be considered one form of VR, AR, or both, the VR/AR world has carried a reputation over the years as either being futuristic or just part of a small specialty or hobby industry.
When viewing digital images on a mobile view screen, like a Head Mounted Display (HMD), the effect of immersing a user in a virtual reality world with part of the digital world viewed that is not related in some way with the “real” world of the user can limit the experience, frustrate the user, or in some cases cause sickness. For example, an HMD with head tracking attempts to register a user's view and physical position within the digital world being seen by the user wearing the HMD, but delays in screen display responsiveness to position and orientation, as it relates the user's physical position or movement, produces an unsettled, uncomfortable sensation, similar to vertigo where the viewed world is out of sync with the viewer. Thus, enabling tablets and smartphones to be fully capable of VR/AR that accurately places the person's viewpoint in the computer generated environment in relation to its position in real world, helps to eliminate sicknesses that are related to VR/AR HMD applications, since tablets and smartphones do not entirely cover the field of vision of the user with the computer graphic (CG) image.
In addition to the physiological effects from the image display lag experienced in VR and AR applications that use HMD, or in VR glasses with position-registered head tracking, the cost of typical head tracking systems are extremely expensive. Typically, a VR system that uses an HMD to provide spatial registration of a user's viewpoint for a more immersive, realistic experience utilizes an optical tracking solution to track the user's HMD position and register that position with a virtual view displayed on the HMD monitor screen. The optical tracking approach is limited as it usually requires a special light or reflective marker placed on a part of the tracked HMD. This optical approach has several technical limitations such as small working volumes, line of sight dependence, limited freedom of movement, and awkward ergonomics as a result of the requirement for markers on the tracked device (HMD). Also, some of these optical tracking approaches require high speed cameras that are not only expensive, but also suffer from the same technical limitations and require relatively high numbers of cameras to cover the working area.